There is known a matrix converter as a power conversion apparatus for converting ac power to ac power directly and efficiently with a construction requiring a smaller number of component parts and enabling size reduction of the apparatus (Patent Document 1).
However, the routing or wiring distance of wires is long for connecting to switching means including IGBT (Insulated Gate Bipolar Transistor), in the above-mentioned matrix converter of earlier technology in which each of the phases (R phase, S phase, T phase) is provided with one of filter condensers forming a filter circuit, and the filter condensers are installed in a unit case.